Soil and Plant Interactions

fa آثار تنش آبی بر رشد، مقدار علوفه و تنوع ژنتیکی سه گروه فنولوژیک فسکیوی بلند (Festuca arundinacea) در منطقه اصفهان Effects of Water Stress on Growth, Forage Yield and Genetic Variation of Three Phenological Groups of Tall Fescue (Festuca arundinacea) in Isfahan Region رشد گیاهان در شرایط تنش Plant growth under stressful conditions پژوهشي Research توانایی تنظیم فنولوژیک و تسریع در رسیدگی یکی از مکانسیم‌های گیاهان برای تحمل به تنش کم‌آبی است. فسکیوی بلند (Festuca arundinacea) از گراس‌های علوفه‌ای و چمنی با ارزش است که برای جلوگیری از فرسایش خاک و نیز تولید علوفه در مراتع استفاده می‌شود و با اکثر خاک‌ها و اقلیم‌ها نیز سازگار است. در این پژوهش، آثار تنش کم‌آبی بر پتانسیل تولید و تنوع ژنتیکی سه گروه مختلف شامل گروه والدینی، گروه زودرس و دیررس گزینش شده از جامعه پایه پلی‌کراس (هر یک شامل 25 ژنوتیپ) از طریق ارزیابی در دو شرایط بدون تنش و تنش کم‌آبی در مزرعه پژوهشی دانشکده کشاورزی دانشگاه صنعتی اصفهان (با عرض جغرافیایی 22 درجه و 32 دقیقه شمالی و طول جغرافیایی 51 درجه و 32 دقیقه شرقی و ارتفاع از سطح دریا 1630 متر) طی سال‌های زراعی 1394 و 1395 بررسی شد. اعمال تنش در 90 درصد تخلیه آب قابل استفاده خاک انجام شد و در شرایط بدون تنش در 50 درصد تخلیه آب قابل استفاده خاک، آبیاری انجام شد. نتایج نشان داد که تنوع چشمگیری بین ژنوتیپ‌ها از لحاظ صفات مطالعه شده و پاسخ به تنش کم‌آبی وجود دارد. بیش‌ترین مقدار تنوع ژنتیکی مربوط به صفت وزن علوفه بود. وزن علوفه خشک در چین اول و دوم در اثر تنش کم‌آبی به‌ترتیب 17 و 52 درصد کاهش پیدا کرد. بیش‌ترین برآورد وراثت‌پذیری مربوط به صفت روز تا گرده‌افشانی و کم‌ترین آن مربوط به درصد ماده خشک و وزن علوفه بود. بیش‌ترین میزان علوفه خشک در شرایط بدون تنش رطوبتی مربوط به گروه دیررس بود. نتایج مقایسه میانگین نشان داد که تحت شرایط بدون تنش و تنش رطوبتی، بیش‌ترین وزن علوفه علوفه خشک در گروه زودرس به‌ترتیب متعلق به ژنوتیپ‌های آمریکا (209/50 گرم در بوته) و یاسوج 2 (142/25 گرم در بوته)، در گروه دیررس به‌ترتیب ژنوتیپ‌های سمنان-شاهرود 4 (383 گرم در بوته) و لهستان 1 (178/50 گرم در بوته) و در گروه والدینی (میان‌رس) ژنوتیپ سمنان-شاهرود 4 به‌ترتیب با میانگین 222/50 و 182/25 گرم در بوته دارا بودند. نتایج این پژوهش نشان می‌دهد که ژنوتیپ‌های مورد بررسی دارای خواب ناقص تابستانی هستند که بایستی در پژوهش‌های بعدی مورد بررسی قرار گیرند. از تنوع ژنتیکی زیاد بین و درون گروه‌های فنولوژیک و پاسخ متفاوت آن‌ها به تنش می‌توان برای توسعه ارقام ساختگی مناسب کشت در خاک‌های دارای محدودیت منابع آبی و نیز جلوگیری از فرسایش در مراتع استفاده کرد.   Abstract The ability of phenological adjustment and accelerate maturation is one of the most drought tolerance mechanisms in crops. Tall fescue is one of the valuable forage and turf grasses that is used to prevent soil erosion and produce forage in pastures and is compatible with most soils and climates. In this research, yield potential and genetic variation of three phenological groups including mid-flowering group (parental group), early and late flowering groups each containing 25 genotypes, selected from a poly cross community, were studied under non-stress and water deficit conditions in the research farm of Isfahan University of Technology for two years. Irrigation was applied when 90 and 50% of available soil water were depleted for stress and normal environments, respectively. The results showed that there was considerable variation in the studied germplasms in terms of all studied traits and responses to water deficit stress. The highest value of genetic variation belonged to forage yield. The results showed that dry forage yield in the first and second harvest stress decreased by 17% and 52% due to water deficit, respectively. The highest estimate of heritability was related to the trait of day to anthesis and the lowest was related to the percentage of dry matter and forage yield. The results showed that the highest dry forage yield under non-stress conditions belonged to the late flowering group. Means comparison of genotypes showed that the highest dry forage yield under normal and water stress belonged to genotypes 10 (from America with 209.50 g/plant) and 3 (from Yasouj with 142.25 g/plant), respectively, in the late flowering group, genotypes 25 (from Shahrood with 383 g/plant) and 22 (from Poland with 178.50 g/plant), respectively in early flowering group and genotypes 25 (from Shahrood) with 222.50 and 182.25 g/plant in the parental group, respectively. The results indicate that the studied genotypes may have incomplete summer dormancy that should be investigated in future studies. Considerable genetic diversity between and within phenological groups and their different responses to drought stress can be used to develop and produce suitable synthetic varieties for soils with limited water resources. Background and Objective: Plant water deficits may occur as a consequence of a seasonal decline in soil water availability, developing in the long term, or may result from drought spells (1). Tall fescue (Festuca arundinacea Schreb), the most important forage and turf grass species, is a widely used grass species that can be found abundantly in cold and dry regions (3). Tall fescue has a deep root system compared to other cool-season grasses. It has become an important grass for turf and <a href="https://en.wikipedia.org/wiki/Soil_conservation" style="color:blue; text-decoration:underline" title="Soil conservation">soil conservation</a>. Tall fescue is well cultivated in acidic soils with a pH equal to 4.8 to alkaline soils with a pH of 9.5 (2). In this research, the yield potential and genetic diversity of three different phenological groups of tall fescue genotypes were studied under non-stress and water deficit conditions. Methods: Three different tall fescue groups in terms of phenology, each contained 25 genotypes, mid-flowering group (parental group), early and late flowering groups, selected from a polycross nursery, were studied under non-stress and water deficit conditions in the research farm of Isfahan University of Technology for two years.  In non-stress and water deficit stress conditions, irrigation was applied when 50% and 90% of the total available water was depleted from the root zone, respectively. Results: The results of the analysis of variance revealed highly significant (p < 0.01) difference among the cultivars for the studied traits. Also, the interaction between cultivar and environment was significant for all the studied traits. The highest value of genetic variation belonged to dry forage yield. Water deficit stress significantly reduced dry forage yield in the first and second harvest by 44.80 and 18.28%, respectively. The highest estimate of heritability was related to the days to anthesis, and the lowest one was related to the percentage of dry matter and forage yield. The results showed that the highest dry forage yield under non-stress conditions belonged to the late flowering group but in the case of water deficit stress there was no significant difference between the early and late flowering groups. Also, the parental group showed the lowest percentage of yield reduction under moisture-stress conditions. A comparison of means showed the highest dry forage yield mean in the early-flowering group was related to genotypes 10 (with 209.50 g/plant) and 3 (with 142.25 g/plant) under non-stress and water deficit stress conditions, respectively. In late-flowering group, genotypes 25 (with 383 g/plant) and 22 (178.50 g/plant) had the highest dry forage yield under non-stress and water deficit stress conditions, respectively. Also, in the parental group, genotypes 25 had the highest dry forage yield with 222.50 and 182.25 g/plant under non-stress and water deficit stress conditions, respectively. Conclusions: High variation in the studied germplasm for response to water deficit stress can be used to develop suitable cultivars in soils with limited water resources. Water deficit stress significantly reduced forage yield and important traits of tall fescue. However, the reaction of different genotypes to water deficit stress is different so it is possible to find tolerant and high-yielding genotypes suitable for cultivation in different regions. Water deficit stress reduced forage plant weight by 27%, 35%, and 7% in late, early, and parental groups, respectively. Genotypes of the parental group with the lowest percentage of yield reduction under water stress conditions can be assessed to select tolerant cultivars to water stress in future studies. The results of this study indicate that the studied genotypes may have incomplete summer dormancy that should be investigated in future studies. Considerable genetic diversity between and within phenological groups and their different responses to drought stress can be used to develop and produce suitable synthetic varieties for soils with limited water resources. References: 1. Chaves, M.M., Oliveira, M.M., 2004. Mechanisms underlying plant resilience to water deficits: prospects for water-saving agriculture. Journal of Experimental Botany 55(47): 2365–2384. 2. Khashij, Sh., Karimi, B., Makhdoumi, P., 2018. Phytoremediation with Festuca arundinacea. International Journal of Health and Life Sciences 4(2): 1–7. 3. Nematollahia, F., Tehranifara, A., Nematia, S.H., Kazemia, F., Gazanchianb, Gh.A., 2018. Improving early growing stage of Festuca arundinacea Schreb. using media amendments under water stress conditions. Desert 23(2): 295–306.   فستوکا, فنولوژی, تنش رطوبتی, مرتع. Festuca, Phenology, Water stress, Pasture. 23 40 http://jspi.iut.ac.ir/browse.php?a_code=A-10-360-1&slc_lang=fa&sid=1 A. Noroozi عباس نوروزی abbas.noroozi22@yahoo.com No Department of Agronomy and Plant Breeding, College of Agriculture, Isfahan University of Technology, Isfahan, 84156-83111, Iran. گروه زراعت و اصلاح نباتات، دانشکده کشاورزی، دانشگاه صنعتی اصفهان، ایران M.M. Majidi محمد مهدی مجیدی majidi@iut.ac.ir Yes Department of Agronomy and Plant Breeding, College of Agriculture, Isfahan University of Technology, Isfahan, 84156-83111, Iran. گروه زراعت و اصلاح نباتات، دانشکده کشاورزی، دانشگاه صنعتی اصفهان، ایران F. Ebrahimi فاطمه ابراهیمی fa.ebrahimi@uk.ac No Research & Technology Institute of Plant Production, Shahid Bahonar University of Kerman, Iran. پژوهشکده فناوری تولیدات گیاهی، دانشگاه شهید باهنر کرمان، ایران